Iraq says three car bombs ripped through an outdoor market in Mosul on Thursday, killing at least 15 civilians and eight policemen.

Debris was left strewn across the road at the scene of the attack, including the shells of several destroyed cars. Armed soldiers were stationed around the site of the attack.

The Defense Ministry said Thursday's attack occurred in the eastern Gogjali district, which Iraqi forces retook from ISIS militants weeks ago as part of a massive operation to drive them from the country's second largest city.

It did not say whether the explosions were caused by suicide attackers.

Earlier on Thursday, the United Nations denounced the killing of four aid workers and seven other civilians in two mortar attacks in Mosul this week. The UN mission said the attacks occurred on Tuesday and Wednesday in eastern Mosul, and wounded up to 40 others.